Effect of Sample Size on Measurement Reliability of Microwave Dielectric Properties of Low-Loss Materials by a Resonant Cavity Method

Abstract

The microwave dielectric properties of SrTiO 3 and CaNdAlO 4 single crystals were measured by the resonant cavity method, and the effect of sample size on measurement reliability was investigated. High measurement accuracy could always be achieved for SrTiO 3 , while the measurement was completely unreliable for CaNdAlO 4 with small sizes. The difference was attributed to the much higher dielectric constant and electric energy filling factor of SrTiO 3 . It is indicated that the sample with much smaller size than usual might also be used for the resonant cavity method, as long as the electric energy filling factor of the sample was high enough.

Millimeter‐wave dielectric characteristics of Sr1−xCaxSmAlO4 ceramics

“…where Q u and tan δ represent the unloaded quality factor and the dielectric loss of samples, respectively. 15,16 In this work, P e and Q c /Q u were higher than 0.94 and 4.5, respectively for all measurements, which indicates the high reliability of the measured Qf value.…”

“…The Q values at 7–15 GHz were determined by using the silver‐plated copper cavity with a dimension of 23.6 mm in diameter and 11.8 mm in height and the samples with a diameter of ∼10 mm and thickness of 5 mm, while the Q values at 15 to 28 GHz were determined by a half‐size resonant cavity and samples. The value of electrical filling factor P e and quality factor of conducting metal walls Q c determine the measurement reliability of the Q value, $$$$\begin{equation}\frac{1}{{{{Q}_{\mathrm{u}}}}} = {{P}_e}\ \tan \delta + \frac{1}{{{{Q}_{\mathrm{c}}}}},\end{equation}$$$$where Q u and tan δ represent the unloaded quality factor and the dielectric loss of samples, respectively 15,16 . In this work, P e and Q c / Q u were higher than 0.94 and 4.5, respectively for all measurements, which indicates the high reliability of the measured Qf value.…”

“…1,2 So far, a number of microwave dielectric ceramics have been developed for sub-6 GHz applications, where high ε r is generally required to meet the needs for device miniaturization. On the other hand, because of the general development trend of the future mobile communication is toward millimeter-wave range, 3 high ε r is no longer required, and a low ε r (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20), high Q-value (∼5 000 at working frequency) combined with a near-zero τ f are required for the microwave dielectric ceramics for millimeter-wave applications. 2 MgAl 2 O 4 , Mg 2 SiO 4 , and Zn 2 SiO 4 have been investigated as the typical microwave dielectric ceramics with a dielectric constant below 10.…”

Structure and microwave dielectric characteristics of Hf1‐xTixO2 ceramics

“…where Q u and Q c are the unloaded quality factor and the quality factor of conducting cavity walls, respectively, and P e and Q are the electrical filling factor and quality factor of the sample, respectively. 24 P e and Q c /Q u were higher than 0.92 and 5.5, respectively, for all the measurements, indicating the measurement reliability of the Qf value.…”

“…The small samples and resonant cavity were used to avoid difficulties in analyzing TE 0np modes with large n or p values. The measurement reliability of Qf value by the resonant cavity method with TE 01δ and high‐order TE 0np modes can be estimated by the values of P e and Q c / Q u in where Q u and Q c are the unloaded quality factor and the quality factor of conducting cavity walls, respectively, and P e and Q are the electrical filling factor and quality factor of the sample, respectively 24 . P e and Q c /Q u were higher than 0.92 and 5.5, respectively, for all the measurements, indicating the measurement reliability of the Qf value.…”